How do you conjugate verbs in the preterit?
i need a really good explanation and can you include different verbs like ar, ir, and er?

To conjugate verbs in the preterite tense you just have to remove the infinitive endings and add the correct preterit ending depending on who the subjects of the action is. You already know the different verb endings ar ir and er. ir and er verbs have the same preterite endings
The different subjects are
1.yo
2. tú
3.usted, él, ella
4. nosotros
5. vosotros
6. ustedes, ellos, ellas

For ar verbs yo would drop the ar and add the ending accordingly so for
1. Yo the ending would change to -é
2. tú the ending would change to -aste
3. usted, él, ella the ending would change to -ó
4. nosotros the ending would change to -amos
5. vosotros the ending would change to -asteis
6. ustedes, ellos, ella, the ending would change to -aron

For the ir and er verbs, you would drop the ir or er and add
1. Yo the ending would change to  -í
2. tú the ending would change to -iste
3. usted, él, ella the ending would change to -ió
4. nosotros the ending woul change to - imos
5. vosotros the ending would change to -isteis
6. ustedes, ellos, ellas the ending would change to -ieron

An example would be an ar verb viajar
1. Yo viajé
2. Tú viajaste
3. Él (ella, ud.) viajó
4. Nosotros viajamos
5. Vosotros viajasteis
6. Ellos (ellas, uds.) viajaron

The answer to your following question is carpet.

There are many examples of how latin influence has come to america and is here to stay. one for example is the banana. a fruit that was only grown in south america for years but then came to america in the early 1900s. it was propagandized as an exotic fruit from latin america during the first world war and took america by storm. now bananas are wildly used in the united states as one of the most popular fruits. another example is clothing. now more than ever ponchos, tribal prints from latin american latinos (such as mexico, peru, honduras, colombia, etc) are popularizing the colorful prints the latin american indigenous people would use, on back packs, sweaters, jewelry, blankets, etc in the "hipster movement." these things were originally popularized in the 90s after a mass movement of immigration after the regan administrations amnesty. but this trend continues in america today.